Chris Kelly's death may have been caused in part by cocaine and heroin abuse, authorities say. The 34-year-old Kris Kross rapper was found unresponsive at his Atlanta-area home on Wednesday, May 1, and later died at a nearby hospital.

A police report obtained by TMZ says Kelly had been using a combination of cocaine and heroin, known as a "speedball," the night before his death.

According to the report, Kelly's mother, Donna Kelly Pratt, was the one who called 911 and told police about her son's drug use. She allegedly told investigators that Kelly had an "extensive history of drug use," and she had taken him home to recover before he passed out.

Donna told Us Weekly in a statement: "It is with deep sadness that we announce that our beloved Chris Kelly has passed away on May 1. To millions of fans worldwide, he was the trendsetting, backwards pants-wearing one-half of Kris Kross who loved making music. But to us, he was just Chris — the kind, generous and fun-loving life of the party. Though he was only with us a short time, we feel blessed to have been able to share some incredible moments with him. His legacy will live on through his music, and we will forever love him."

Childhood friends Kelly and Chris Smith formed Kris Kross at the age of 13 after being discovered in an Atlanta mall in 1991 by producer Jermaine Dupri. The rap duo's 1992 hit "Jump" went double platinum.